分布式光伏并网装置的研制

Development of distributed photovoltaic grid-connection device

设计了基于ARM Cortex-M4内核32位芯片的双CPU分布式光伏并网装置,包括主控CPU、通信CPU。通过模块化设计、集成数据采样处理,实现装置与配电网调度中心及逆变器等智能装置的信息交互,具备带方向和复压闭锁过流保护、逆功率保护、零序电流保护、过负荷保护、被动式防孤岛保护、同期并网等功能。考虑分布式光伏电站对同期并网的高要求,提出了基于采样点相角差预测捕捉合闸点的差频并网算法。微机继电保护系统测试结果表明,所设计装置能够准确地进行数据采集、保护可靠动作;相较于传统差频并网算法,所提预测算法能够有效地提高并网精度。

The distributed photovoltaic grid-connected device with dual-CPU is designed based on ARM Cortex-M4 core 32 bit chip, including master control CPU and communication CPU. By modular design and sampling of inte- grated data, the device can realize information interaction with dispatch center of distribution network, inverters and other intelligent devices, and has the functions of direction and compound voltage blocking overcurrent protection, re- verse power protection, zero sequence current protection, overload protection, passive anti-islanding protection, syn- chronization grid-connection, and so on. Considering the high requirement of distributed photovohaic plant on syn- chronization grid-connection, the different-frequency grid-connect/on algorithm based on catching closing point based on phase-angle difference prediction of sampling point. Test results of microcomputer relay protection system show that, the designed device can collect data correctly and the protection can act reliably. Compared with the traditional different-frequency grid-connection algorithm,the proposed algorithm can improve the grid-connection accuracy effectively.